If you fail to lock your wifi, doors, windows or automobiles you’re taking a risk. Would it be okay if they compiled a list of houses with unlocked doors and/or windows, and published the list?
The difference is, to access my unlocked doors/windows etc, you have to go onto my private property which I did not grant you permission to.
In the case of WiFi you are transmitting beyond your property onto your neighbors property and very likely public property, like the public street in this case. In addition the very airwaves that you are using are public and are not your private property to begin with.
If you want to use the public airwaves and expect any privacy it is your duty, and no one else’s, to encrypt your data.